Can't downgrade. It's not possible.
I'm also having issues after upgrading to 42.19.
My mistake was I deleted the old map & now, the iPure9(1) is unable to return to base after mapping. Failure to return to charging base after mapping prevents me from saving the map.
Please fix the bugs or at least do not 'force' users to upgrade if there is no need to do so. Why fix something when it is not even broken?
How do I do a software update? There is nowhere in the ap that I can see the option to do an update?